The cellular prion protein binds copper in vivo
Abstract
The normal cellular form of prion protein (PrPC) is a precursor to the pathogenic protease-resistant forms (PrPSc) believed to cause scrapie, bovine spongiform encephalopathy (BSE) and Creutzfeldt-Jakob disease1. Its amino terminus contains the octapeptide PHGGGWGQ, which is repeated four times and is among the best-preserved regions of mammalian PrPC. Here we show that the amino-terminal domain of PrPCexhibits five to six sites that bind copper (Cu(II)) presented as a glycine chelate. At neutral pH, binding occurs with positive cooperativity, with binding affinity compatible with estimates for extracellular, labile copper. Two lines of independently derived PrPCgene-ablated (Prnp0/0) mice exhibit severe reductions in the copper content of membrane-enriched brain extracts and similar reductions in synaptosomal and endosome-enriched subcellular fractions. Prnp0/0mice also have altered cellular phenotypes, including a reduction in the activity of copper/zinc superoxide dismutase and altered electrophysiological responses in the presence of excess copper. These findings indicate that PrPCcan exist in a Cu-metalloprotein form in vivo.
- Publication:
-
Nature
- Pub Date:
- December 1997
- DOI:
- 10.1038/37783
- Bibcode:
- 1997Natur.390..684B